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What is oil pressure suppose to be at? stock ej257

8.2K views 11 replies 7 participants last post by  knyg  
#1 ·
So recently I noticed I was running really low on oil (like bad, probably only had 2 litres in. Yes, I am dripping oil from my sandwich adapter) and the oil pressure gauge (if I remember correctly) was about 40psi hot / 80 psi cold. I have now changed my oil and the gauge is at 90-100 psi cold, forgot what it runs at when hot.

I was under the assumption that the less amount of oil you have, the psi would be higher since it has to pump harder to move the oil. Does the oil pump only pump at one fixed rate?

My main question is: What should the oil pressure be at when hot/cold on a stock ej257? My gauges measure from a sandwich adapter between the car and oil filter.
 
#2 ·
Oil pressure will not change due too oil level - until it is low enough to cause damage - IE the pickup is not in the oil all the time. 2l low might well be low enough to do that if you are driving hard.

normal il pressure limit is app 80 at rpm, often under 20 in heat at idle
 
owns 2020 Subaru STI
#3 · (Edited)
With low oil, I was driving normal on street use. So I hope there isnt any significant damage. But I think it ran like that for about 1,000 miles.

Right now, on start-up the oil pressure is abut 100psi. It does drop to about 40psi while driving and 20psi idle.


edit: when my oil is 200F the driving oil pressure is about 80-90psi and then 30psi idle.
 
#4 ·
Bob the oil guy wrote you should be sure to have at least 10psi/Krpm don't know if that was design specific or a minimum. He was referring to Porsche, but the discussion sounded generic. What do I know?
 
owns 2020 Subaru STI
#5 ·
I am not too concerned about the minimum oil pressure. Hopefully I will never get that low or run the engine dry. I am wondering what is the optimal range oil pressure should be at during operation. Does it matter? as long as it is not too low or too full? What are the effects of having high oil pressure, like 100psi+ constantly?
 
#6 ·
As silly as this sounds.....I believe oil pressure readings will vary. What your oil pressure gauge will read will vary depending on the location of the sending unit/transducer/sensor, the sensor itself, how its reading, and even what kind of oil being used. Ive gathered this based on my own experiences.

Back when I ran a sandwitch plate adaptor on the oil filter/cooler my readings were what I considered "normal". I had the transducer with a braided oil line getting a reading from the sandwitch plate. Around 34psi idle operating temp, and then around 94ish at operating temp crusing at 3K rpms in 6th gear at 70mph. Then the reading changed when I removed the sandwitch plate and put the transducer to the gallery spot behind the intake manifold underneath the TMIC. Readings got lower and much different when using that location. The reading once again changed when I used a different oil pressure transducer, again lower this time too. Then it changed again and went even lower once I switched oils from Rotella T6 to Motul. Both oils being 5w40 btw. Now a days, my oil pressure reading at operating temp at idle is around 24ish and around 84ish or so when cruising at 70mph, 3K in 6th gear. Something to keep in mind, im using an old school tech lol. I have the Maddad oil pressure gauge along with a cheap ebay oil pressure transducer and prosport braded oil line. Nothing fancy about my set up lol.

Unless you are using a direct mechanical gauge to the block every time, the readings will vary.
 
#11 ·
You're likely fine, as long as the oil level did not drop low enough to cause starvation.

Oil pressure will drop some once oil level gets really low (less oil doing the same work = more heat). There is a significant amount of oil in the pan constantly. You're not pushing it all through the lubrication system.

The line in the sand is 14psi at hot idle. Cold is going to vary, but your pressures are in-line with normal.